Hi welcome to HCM... If having history of unprotected sexual intercourse than pregnancy should be ruled out first by urinary card for detection of Hcg .... If pregnancy not present than detail work up needed according to pelvic and per speculum examination.... USG will be beneficial in rule out ovarian cyst , PID , fibroid etc if present ... If needed vaginal swab taken and send for culture ... Excess stress sometime can lead delay period ... Rule out diabetis and thyroid problem by blood sugar estimation and thyroid profile ... If still needed hormonal profile done for checking hormonal imbalance . Advise : consult gynecologist for examination.... Take care